The crystal structure of [(CH3)4N]4Na2H[α-PW11O39]·8H2O has been determined by using the Weissenberg camera at the BL04B2 beamline of SPring-8, revealing that it contains a disorder-free lacunary [α-PW11O39]7− anion with one sodium cation embedded into its lacuna that links the oxometalate building blocks into a one-dimensional chain, which is then woven into a three-dimensional latticework by another Na+.
